It is a mixed-use building with a pre-existing/grandfathered commercial portion that will be converted to residential shortly after move-in.

I also wanted a space that had pre-existing plumbing in the basement, even if it wasn't finished, so it would be simpler for my contractor to create a bathroom/wet bar setup that would work for a future renter (if there wasn't a pre-existing bathroom).

Also, a full title search at that time may reveal preexisting title issues.

Based on your priorities, pre-existing relevant experience in other fields, and general interests or niche preferences, you should ask questions about what resources and support are offered that will help you ultimately obtain your goals.

PM allowed a pre-existing Tenant to go month-to-month without a rent increase, new lease, pet fees, inspection, etc? 

Perhaps this person would need a large discouragement to pay you off before assuming the pre-existing mortgage. 

I suggest having a consultation with an experienced landlord-tenant attorney that services the area you wish to purchase.Are there any preexisting issues with this tenant you're aware of?  

Here is the big one, pre-existing condition, this is the insurance company's golden ticket for getting out of large ticket claims.

It had a pre-existing tenant who was there for the past few years.He's been fine for the most part, signed a new lease in January with a very minor increase (I think 25 bucks).However, the last four months he's been late with the rent. 

--The seller gets $100k (minus closing costs)(Note: the seller has to pay off any liens on the property, such as pre-existing mortgages, to be able to sell it free and clear.